The invention relates to a concentrated emulsion for making an aqueous hydrocarbon fuel emulsion. More particular the invention relates to a process for making an aqueous hydrocarbon fuel involving the pre-emulsification of a concentrated emulsion that is then diluted by the external fuel phase.
Diesel fueled engines produce NOx due to the relatively high flame temperatures reached during combustion. Nitrogen oxides are an environmental issue because they contribute to smog and pollution. Governmental regulation and environmental concerns have driven the need to reduce NOx emissions from engines. Non-attainment areas such as California and Houston and heavily regulated areas such as Mexico City, the UK, and Germany would most benefit by emissions reductions. The reduction of NOx production includes the use of catalytic converters, using xe2x80x9ccleanxe2x80x9d fuels, recirculation of exhaust and engine timing changes. These methods are typically expensive or complicated to be commercially used.
Internal combustion engines, especially diesel engines, using water mixed with fuel in the combustion chamber can produce lower NOx, hydrocarbon and particulate emissions per unit of power output. Water is inert toward combustion, but lowers the peak combustion temperature resulting in reduced particulates and NOx formation. The water in fuel emulsion reduces the NOx emissions in diesel engines by approximately 5-20% and particulates 20-50%.
When water is added to the fuel it forms an emulsion and these emulsions are generally unstable. Stable water-in-fuel emulsions of small particle size are more difficult to reach and maintain. It would be advantageous to make a stable water-in-fuel emulsion that can be stable in storage.
It would be advantageous to produce a stable water-in-fuel emulsion that has optimum stability and at a good throughput rate. Applicant""s current process disclosed in the prior applications listed above utilizes a process in which the total amount of water, fuel and emulsifiers are emulsified to produce a fully formulated aqueous hydrocarbon fuel emulsion. It has been discovered that adding a portion of the fuel initially with the total amount of water and total amount of emulsifiers to form a concentrated emulsion, and then later adding the final portion of fuel to the concentrated emulsion results in improved emulsion stability of the fully formulated water in fuel blend. Further, preparing a concentrated emulsion that is then diluted with the final portion of fuel, increases the throughput by allowing for the production of a greater quantity of fully formulated water-blended fuel product.
The invention relates to a concentrated aqueous hydrocarbon emulsion comprising:
(1) a portion of a total amount of a hydrocarbon fuel contained in the fully formulated aqueous hydrocarbon fuel emulsion,
(2) substantially all of an emulsifier contained in the fully formulated aqueous hydrocarbon fuel emulsion wherein the emulsifier is selected from the group consisting of (i) at least one fuel-soluble product made by reacting at least one hydrocarbyl-substituted carboxylic acid acylating agent with ammonia or an amine, the hydrocarbyl-substituted acylating agent having about 50 to about 500 carbon atoms; (ii) at least one of an ionic or non-ionic compound having a hydrophilic-lipophilic balance of about 1 to about 40; (iii) a mixture of (i) and (ii); or (iv) a water-soluble compound selected from the group consisting of amine salts, ammonium, azide compounds, nitro compounds, nitrate esters, nitramine, alkali metal salts, alkaline earth metal salts and mixtures thereof in combinations with (i), (ii) or (iii); and
(3) substantially all of a water contained in the fully formulated aqueous hydrocarbon fuel emulsion wherein the water is selected from the group consisting of water, water/antifreeze, water/ammonium nitrate, or combinations thereof, resulting in a concentrated aqueous hydrocarbon emulsion used to make the fully formulated aqueous hydrocarbon fuel emulsion.
The invention further relates to a process for the production of an aqueous hydrocarbon fuel emulsion from a concentrated aqueous hydrocarbon fuel emulsion comprising:
(1) preparing a concentrated aqueous hydrocarbon fuel emulsion comprising emulsifying;
(a) a portion of a hydrocarbon fuel in the range of about 0.5% to about 70% by weight in the fully formulated aqueous hydrocarbon fuel emulsion;
(b) substantially all of an emulsifier in the range of about 0.05% to about 20% by weight of the fully formulated aqueous hydrocarbon fuel emulsion wherein the emulsifier is selected from the group consisting of (i) at least one fuel-soluble product made by reacting at least one hydrocarbyl-substituted carboxylic acid acylating agent with ammonia or an amine, the hydrocarbyl-substituted acylating agent having about 50 to about 500 carbon atoms; (ii) at least one of an ionic or non-ionic compound having a hydrophilic-lipophilic balance of about 1 to about 40; (iii) a mixture of (i) and (ii); or (iv) a water-soluble compound selected from the group consisting of amine salts, ammonium salts, azide compounds, nitro compounds, nitrate esters, nitramine, alkali metal salts, alkaline earth metal salts and mixtures thereof in combination with (i), (ii) or (iii); and
(c) substantially all of water in the range of about 5% to about 50% by weight of the fully formulated aqueous hydrocarbon fuel emulsion wherein the water is selected from the group consisting of water, water/antifreeze, water/ammonium nitrate, and combinations therein,
to form a concentrated aqueous hydrocarbon fuel emulsion with a water particle size having a mean diameter of less than 1 micron;
(2) diluting the concentrated aqueous hydrocarbon fuel emulsion with the remaining portion of hydrocarbon fuel in the range of about 95% to about 50% by weight in the fully formulated aqueous hydrocarbon fuel emulsion,
resulting in a fully formulated aqueous hydrocarbon fuel comprising about 50% to about 99% by weight liquid hydrocarbon fuel and about 1% to about 50% by weight water.
The invention further provides for a continuous or batch process for making a fully formulated aqueous hydrocarbon fuel emulsion from a concentrated aqueous hydrocarbon fuel emulsion.
The invention relates to a concentrated aqueous hydrocarbon fuel emulsion. The concentrated aqueous hydrocarbon fuel emulsion contains a portion of the total hydrocarbon fuel contained in the fully formulated aqueous hydrocarbon fuel emulsion. The portion of hydrocarbon fuel in the concentrated aqueous hydrocarbon emulsion is in the range of about 0.5% to about 70% by weight of the fully formulated aqueous hydrocarbon fuel emulsion, in another embodiment in the range of about 5% to about 40% by weight of the fully formulated aqueous hydrocarbon fuel emulsion, and in another embodiment, in the range of about 5% to about 20% by weight of the fully formulated aqueous hydrocarbon fuel emulsion.
The concentrated aqueous hydrocarbon emulsion contains the total amount of emulsion and in another embodiment substantially all of the emulsifier. A small amount of emulsifier may optionally be added to the fully formulated aqueous hydrocarbon fuel emulsion, the hydrocarbon fuel or combinations thereof. The emulsifier is in a range of about 0.05% to about 20% by weight of the fully formulated aqueous hydrocarbon fuel emulsion, in one embodiment in the range of about 0.1% to about 10% by weight of the fully formulated aqueous hydrocarbon emulsion, in another embodiment in the range of about 1% to about 10% by weight of the fully formulated aqueous hydrocarbon fuel emulsion, and in another embodiment in the range of about 1% to about 5% by weight of the fully formulated aqueous hydrocarbon fuel emulsion.
The emulsifier is selected from the group consisting of (i) at least one fuel-soluble product made by reacting at least one hydrocarbyl-substituted carboxylic acid acylating agent with ammonia or an amine, the hydrocarbyl-substituted acylating agent having about 50 to about 500 carbon atoms; (ii) at least one of an ionic or non-ionic compound having a hydrophilic-lipophilic balance of about 1 to about 40; (iii) a mixture of (i) and (ii); or (iv) a water-soluble compound selected from the group consisting of amine salts, ammonium salts, azide compounds, nitro compounds, nitrate esters, nitramine, alkali metal salts, alkaline earth metal salts and mixtures there in combinations with (i), (ii) or (iii).
The concentrated aqueous hydrocarbon emulsion contains the total amount of water and in another embodiment substantially all of the water. The water is in the range of about 1% to about 50% by weight of the fully formulated aqueous hydrocarbon fuel emulsion, in one embodiment in the range of about 15% to about 50% by weight of the fully formulated aqueous hydrocarbon fuel emulsion, and in another embodiment in the range of about 35% to about 50% by weight of the fully formulated aqueous hydrocarbon fuel emulsion. The water is selected from the group consisting of water, water antifreeze, water ammonium nitrate or combinations thereof. A small amount of may be added to the fully formulated aqueous hydrocarbon emulsifier, the hydrocarbon fuel or combinations thereof.
The concentrated aqueous hydrocarbon emulsion has a shelf life at ambient conditions for at least one year, and in another embodiment for greater than one year.
The invention further relates to a process for the production of an aqueous hydrocarbon fuel from the concentrated aqueous hydrocarbon fuel emulsion. The concentrated aqueous hydrocarbon emulsion contains a portion of the total hydrocarbon fuel contained in the fully formulated aqueous hydrocarbon fuel emulsion. The process involves preparing the concentrated aqueous hydrocarbon fuel emulsion. A portion of the hydrocarbon fuel is emulsified with the total quantity of emulsifier and the total quantity of water in the fully formulated aqueous hydrocarbon fuel emulsion. The portion of hydrocarbon fuel added to make the concentrated aqueous hydrocarbon emulsion is in the range of about 5% to about 50%, in another embodiment in the range of about 5% to about 40%, and in another embodiment in the range of about 1% to about 20% by weight of the fully formulated aqueous hydrocarbon fuel emulsion.
Substantially all of the emulsifier is added to the portion of hydrocarbon fuel. Small amounts of emulsifier may optionally be added to the fully formulated aqueous hydrocarbon emulsion, the hydrocarbon fuel or combination thereof. The emulsifier is in the range of about 0.05% to about 20%, in another embodiment about 0.1% to about 10%, and in another embodiment about 0.5% to about 5% by weight of the formulated aqueous hydrocarbon fuel product.
Optionally, additives may be added to the emulsifier, the fuel, the water or combinations thereof dependent upon the solubility of the additives. The additives include but are not limited to cetane improvers, organic solvents, antifreeze agents, stabilizers, surfactants, other additives known for their use in fuel and the like. The additives are added to the emulsifier, hydrocarbon fuel or the water prior to or in the alternative during emulsification or, in another embodiment, top treated to the fully formulated emulsion. The additives are generally in the range of about 0.00001% to about 10% by weight, in another embodiment about 0.0001% to about 10% by weight, and in another embodiment about 0.001% to about 10% by weight of the fully formulated aqueous hydrocarbon fuel emulsion.
The hydrocarbon fuel, the emulsifier and/or the additives are then emulsified with the total quantity of water, and in another embodiment substantially all of the water, resulting in a concentrated aqueous hydrocarbon emulsion. The water is added in the range of about 5% to about 50%, in another embodiment about 15% to about 50%, and in another embodiment about 35% to about 50% by weight of the fully formulated aqueous hydrocarbon fuel emulsion. A small amount of water may be added to the fully formulated aqueous hydrocarbon emulsifier, the hydrocarbon fuel or combinations thereof.
The water can optionally include but is not limited to antifreeze, ammonium nitrate or mixtures thereof. The ammonium nitrate is generally added to the water mixture as aqueous solution and in another embodiment it is added to the emulsifier. The water is added with high shear mixing/emulsification to form the concentrated emulsion.
Emulsification occurs by any known process. The emulsification generally occurs under ambient conditions. The emulsification results in the concentrated aqueous hydrocarbon emulsion having a mean particle droplet size less than or equal to 1 micron, in one embodiment in the range of about of 0.1 micron to about 1 micron, in another embodiment in the range of about 0.1 to about 0.95, in another embodiment in the range of about 0.1 to about 0.8, and in another embodiment in the range of about 0.1 to about 0.7. The emulsification occurs under sufficient conditions to provide such mean droplet particles sizes.
Shearing is a crucial step in producing the aqueous hydrocarbon fuel. Two things generally occur during emulsification; the water is broken up into homogeneous sub-micron particle sizes and the emulsifier is distributed to the aqueous interface so as to stabilize the particle size distribution. The entire water portion and entire emulsifier portion are present during emulsification for the fully formulated aqueous hydrocarbon fuel emulsion to be homogeneous and exhibit improved stability.
Only a fraction of the total fuel is present during emulsification. The concentrated aqueous hydrocarbon emulsion is then diluted with the balance of hydrocarbon fuel portion. The dilution can occur by any general method known in the art such as mixing, blending, agitation, stirring, emulsification and the like. High shearing is not necessary but is optional. The final portion of hydrocarbon fuel is in the range of about 40% to about 95%, in another embodiment about 50% to about 95%, and in another embodiment about 70% to about 95% by weight of the fully formulated aqueous hydrocarbon fuel emulsion. The portion of hydrocarbon fuel blended with the concentrated aqueous hydrocarbon emulsion equals the difference between the total amount of hydrocarbon fuel in the fully formulated aqueous hydrocarbon fuel emulsion and the portion of hydrocarbon fuel contained in the concentrated aqueous hydrocarbon fuel emulsion. The less hydrocarbon fuel added up front, the larger final product throughput after the balance of the fuel is added.
In the practice of the present invention the aqueous hydrocarbon fuel emulsion is made by a batch or a continuous process. The process is capable of monitoring and adjusting the flow rates of the fuel, emulsifier, additives and/or water to form a stable emulsion with the desired water droplet size.
In a batch process all the water, all the emulsifier and a portion of hydrocarbon fuel is used generally at the shear tank capacity. The batch process of making the concentrate increases the throughput of the fully formulated aqueous hydrocarbon fuel emulsion. The more concentrated the aqueous hydrocarbon emulsion formulizations result in higher batch throughput because of the incremental increase in time cycle is less than the proportional increase in time cycle in fully formulated batch size. For water concentrated processing, batch time is minimized by separating the emulsification phase from the dilution-blending phase. This enables the two processes to occur simultaneously. In another embodiment the concentrated aqueous hydrocarbon fuel emulsion can at a later time be blended with the final portion of fuel. The fully formulated emulsion from the concentrated emulsification gives a significantly more stable product than conventional processing.
The concentrated emulsion can also be prepared in a continuous process and demonstrates equal or greater stability performance than the current approaches. There is an increased throughput by using a continuous process. The continuous process eliminates the need for additional time that is needed in batch processing multiple tank turnovers.
The process may be in the form of a containerized equipment unit that operates automatically. The process can be programmed and monitored locally at the site of its installation, or it can be programmed and monitored from a location remote from the site of its installation. The fully formulated water fuel blend is optionally dispensed to end users at the installation site, or in another embodiment end users can blend the concentrated emulsion with the final portion of fuel. This provides a way to make the aqueous hydrocarbon fuel emulsions available to end users in wide distribution networks.
It is clear that more water concentrated aqueous hydrocarbon emulsification results in higher batch throughput for the incremental increase in time cycle is less than proportional to the increase in final batch size. For water concentrated processing, batch time is minimized by separating the emulsification phase from the dilution blending phase.